Plastics, synthetic fabrics, and synthetic rubber are composed of chemicals that are derived from

Petroleum Products

Petroleum and its products are mainly composed of carbon polymers (chains), as the backbone, with different structural and functional groups. Plastic, for example, is made of polypropylene and polybutylene which is mainly made of carbon atoms, whose monomers are linked in a chain to form polymers that make up the products.
Synthetic rubber on the other hand is made of copolymers of carbon and other addictives such as styrene. Synthetic fiber is made of nylon that is composed of a copolymer between carboxylic acid and amides.

The correct options are :

A)  The biodiversity will decrease because there are fewer species on the newly formed island.

D) The species on the island will likely have lower genetic diversity than the species on the mainland.

Explanation:

When a larger population is broken down and a smaller population is formed, the genetic diversity in the smaller population will be lower as it has fewer species. As a result, options for genetic variations will be lesser. Hence, the landmass which drifted away will have lower biodiversity than the mainland. There will be more number of species on the mainland hence the genetic diversity will be more there.